/**
 * Copyright 1996 self.com.au
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. (http://www.apache.org/licenses/LICENSE-2.0)
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed 
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for 
 * the specific language governing permissions and limitations under the License.
 *
 * <dhamma-message src="Atisha (11th century Tibetan Buddhist master)">
 * 	The greatest achievement is selflessness. The greatest worth is self-mastery.
 * 	The greatest quality is seeking to serve others. The greatest precept is continual awareness.
 * 	The greatest medicine is the emptiness of everything. The greatest action is not conforming with the worlds ways.
 * 	The greatest magic is transmuting the passions. The greatest generosity is non-attachment.
 * 	The greatest goodness is a peaceful mind. The greatest patience is humility.
 * 	The greatest effort is not concerned with results. The greatest meditation is a mind that lets go.
 * 	The greatest wisdom is seeing through appearances. 
 * </dhamma-message>
 *
 * @author Ashin Wimalajeewa
 *
 * Note, this is a very old runtime library that I have evolved since 1996. I rarely use it
 * now because the Apache Commons project has made it obsolete.
 */
package self.math;

public class QuadraticEquation {
  public double a, b, c;
  
  public QuadraticEquation() {
	// nothing to do.
  }
  
  public QuadraticEquation( double a, double b, double c ) {
    setCoefficients( a, b, c );
  }
  
  public void setCoefficients( double a, double b, double c ) {
    this.a = a;
    this.b = b;
    this.c = c;
  }
  
  public void calcXValues( double[] x1Andx2 ) {
    double rootSqrBMinus4ac = getRootOfbSqrdMinus4ac();
    double denominator = 2*a;
    double numerator = -b + rootSqrBMinus4ac;
    x1Andx2[0] = numerator / denominator;
    numerator = -b - rootSqrBMinus4ac;
    x1Andx2[1] = numerator / denominator;
  }

  public double solveForX( double xVal ) {
    return (a*(xVal*xVal)) + (b*xVal) + c;
  }
    
  private double getRootOfbSqrdMinus4ac() {
    double result = 4 * a *c;
    result = b*b - result;
    result = (double) Math.sqrt( result );
    return result;
  }
  
  public String toString() {
    return "[a=" + a + ", b=" + b + ", c=" + c + "]";
  }
}